Camping in the winter in an RV is a challenging experience. In general if things are kept the same way as you would in the other seasons you'll quickly be without a functioning RV. Each time we head out in the winter we end up learning something new, that combined with the resources I've found on the internet is what I hope to catalog here.
Every RV is different. Depending on your manufacturer, type of RV (trailer, class C etc..) you'll run into different problems. Our experiences are with a "four season" Arctic Fox 27t travel trailer.